<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>
    setTimeout(function () {
        console.log('执行异步回调')
    },0);
    for(i=0;i<5000;i++){
        console.log(i)
    }
</script>
</body>
</html>